Waveguide display with a small form factor, a large field of view, and a large eyebox

ABSTRACT

A waveguide display is used for presenting media to a user. The waveguide display includes light source assembly, an output waveguide, and a controller. The light source assembly includes one or more projectors projecting an image light at least along one dimension. The output waveguide includes a waveguide body with two opposite surfaces. The output waveguide includes a first grating receiving an image light propagating along an input wave vector, a second grating, and a third grating positioned opposite to the second grating and outputting an expanded image light with wave vectors matching the input wave vector. The controller controls the scanning of the one or more source assemblies to form a two-dimensional image.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 15/704,190, filed Sep. 14, 2017, which claims the benefit of U.S.Provisional Application No. 62/436,717, filed Dec. 20, 2016, which isincorporated by reference in its entirety.

BACKGROUND

The disclosure relates generally to near-eye-display systems, and morespecifically to waveguide displays with a small form factor, a largefield of view, and a large eyebox.

Near-eye light field displays project images directly into a user's eye,encompassing both near-eye displays (NEDs) and electronic viewfinders.Conventional near-eye displays (NEDs) generally have a display elementthat generates image light that passes through one or more lenses beforereaching the user's eyes. Additionally, NEDs in virtual reality systemsand/or augmented reality systems have a design criteria to be compactand light weight, and to provide a two-dimensional expansion with alarge eyebox and a wide field-of-view (FOV) for ease of use. In typicalNEDs, the limit for the FOV is based on satisfying two physicalconditions: (1) an occurrence of total internal reflection of imagelight coupled into a waveguide and (2) an existence of a first orderdiffraction caused by a diffraction grating element. Conventionalmethods used by the NEDs based on a diffraction grating rely onsatisfying the above two physical conditions in order to achieve a largeFOV (e.g. above 40 degrees) by using materials with a high refractiveindex, and thus, adds significantly heavy and expensive components tothe NEDs. Furthermore, designing a conventional NED with two-dimensionalexpansion involving two different output grating elements that arespatially separated often result in a large form factor. Accordingly, itis very challenging to design NEDs using conventional methods to achievea small form factor, a large FOV, and a large eyebox.

SUMMARY

A waveguide display is used for presenting media to a user. Thewaveguide display includes a light source assembly, an output waveguide,and a controller. The light source assembly includes one or moreprojectors projecting an image light at least along one dimension. Insome configurations, each projector extends a first angular range on afirst plane along a first dimension and a second dimension, and a secondangular range on a second plane along the second dimension and the thirddimension. The output waveguide receives the image light emitted from atleast one of the projectors and outputs an expanded image light to aneyebox (e.g., a location in space occupied by an eye of a user of thewaveguide display) with a rectangular area of at least 20 mm by 10 mm.The output waveguide provides a diagonal FOV of at least 60 degrees. Thecontroller controls the scanning of the light source assembly to form atwo-dimensional image. In some embodiments, the waveguide displayincludes a source waveguide that receives the image light from the lightsource assembly along a first dimension and expand the emitted imagelight along a second dimension orthogonal to the first dimension.

Light from the source assembly is in-coupled into the output waveguidethrough an in-coupling area located at one end of the output waveguide.The output waveguide includes a waveguide body with two oppositesurfaces. The output waveguide includes at least an input diffractiongrating on at least one of the opposite surfaces. The input diffractiongrating in-couples the image light (propagating along an input wavevector) emitted from the light source assembly into the outputwaveguide, and the input diffraction grating has an associated firstgrating vector. In some configurations, there is a single projector, andthe single projector is at a center of the first grating. In alternateconfigurations, the light source assembly includes a first projector anda second projector located along the same dimension with a thresholddistance of separation.

The output waveguide expands the image light in two dimensions. Theoutput waveguide includes a second and third grating (that areassociated with a second and third grating vector, respectively) thattogether direct and decouple the expanded image light from the outputwaveguide. The output waveguide includes at least a first grating thatreceives the image light emitted from at least one of the one or moreprojectors and couples the received image light into the waveguide body,and the waveguide body expands the received image light in at least onedimension to transmit a first expanded image light. Each of the secondgrating and the third grating expands the first expanded image lightalong a different dimension to form a second expanded image light, andoutput the second expanded image light to an eyebox. In someconfigurations, the output expanded image light has a wave vector thatmatches the input wave vector and encompasses the first angular rangeand the second angular range throughout the eyebox along the firstdimension and the second dimension. The input diffraction grating, thesecond grating, and the third grating are designed such that the vectorsum of all their associated grating vectors is less than a thresholdvalue, and the threshold value is close to or equal to zero.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a NED, in accordance with an embodiment.

FIG. 2 is a cross-section of the NED illustrated in FIG. 1, inaccordance with an embodiment.

FIG. 3 illustrates an isometric view of a waveguide display with asingle source assembly, in accordance with an embodiment.

FIG. 4 illustrates a cross-section of the waveguide display, inaccordance with an embodiment.

FIG. 5A illustrates an isometric view of a first design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5B illustrates a top view of the first design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5C illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the first design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5D illustrates an isometric view of a second design of thewaveguide display shown in FIG. 4, in accordance with an embodiment.

FIG. 5E illustrates a top view of the second design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5F illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the second design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5G illustrates an isometric view of a third design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5H illustrates a top view of the third design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5I illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the third design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5J illustrates an isometric view of a fourth design of thewaveguide display shown in FIG. 4, in accordance with an embodiment.

FIG. 5K illustrates a top view of the fourth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5L illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the fourth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5M illustrates an isometric view of a fifth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5N illustrates a top view of the fifth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 5O illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the fifth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 6A illustrates an isometric view of a sixth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 6B illustrates a top view of the sixth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 6C illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the sixth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment.

FIG. 7 illustrates an isometric view of a waveguide display with twosource assemblies, in accordance with an embodiment.

FIG. 8 illustrates a cross-section of waveguide display including twosource assemblies, a portion of two decoupling elements, and twocoupling elements, in accordance with an embodiment.

FIG. 9A illustrates an isometric view of a seventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 9B illustrates a top view of the seventh design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 9C illustrates an example path of grating vectors associated with aplurality of diffraction gratings of the seventh design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 10A illustrates an isometric view of an eighth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 10B illustrates a top view of the eighth design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 10C illustrates an example path of grating vectors associated witha plurality of diffraction gratings of the eighth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 11A illustrates an isometric view of a ninth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 11B illustrates a top view of the ninth design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 11C illustrates an example path of grating vectors associated witha plurality of diffraction gratings of the ninth design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 12A illustrates an isometric view of a tenth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 12B illustrates a top view of the tenth design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 12C illustrates an example path of grating vectors associated witha plurality of diffraction gratings of the tenth design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 12D illustrates an isometric view of an eleventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 12E illustrates a top view of the eleventh design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 12F illustrates an example path of grating vectors associated witha plurality of diffraction gratings of the eleventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 12G illustrates an isometric view of a twelfth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 12H illustrates a top view of the twelfth design of the waveguidedisplay shown in FIG. 7, in accordance with an embodiment.

FIG. 12I illustrates an example path of grating vectors associated witha plurality of diffraction gratings of the twelfth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment.

FIG. 13 is a block diagram of a system including the NED of FIG. 1, inaccordance with an embodiment.

The figures depict embodiments of the present disclosure for purposes ofillustration only. One skilled in the art will readily recognize fromthe following description that alternative embodiments of the structuresand methods illustrated herein may be employed without departing fromthe principles, or benefits touted, of the disclosure described herein.

DETAILED DESCRIPTION

Embodiments of the invention may include or be implemented inconjunction with an artificial reality system. Artificial reality is aform of reality that has been adjusted in some manner beforepresentation to a user, which may include, e.g., a virtual reality (VR),an augmented reality (AR), a mixed reality (MR), a hybrid reality, orsome combination and/or derivatives thereof. Artificial reality contentmay include completely generated content or generated content combinedwith captured (e.g., real-world) content. The artificial reality contentmay include video, audio, haptic feedback, or some combination thereof,and any of which may be presented in a single channel or in multiplechannels (such as stereo video that produces a three-dimensional effectto the viewer). Additionally, in some embodiments, artificial realitymay also be associated with applications, products, accessories,services, or some combination thereof, that are used to, e.g., createcontent in an artificial reality and/or are otherwise used in (e.g.,perform activities in) an artificial reality. The artificial realitysystem that provides the artificial reality content may be implementedon various platforms, including a head-mounted display (HMD) connectedto a host computer system, a standalone HMD, a mobile device orcomputing system, or any other hardware platform capable of providingartificial reality content to one or more viewers

A waveguide display is used for presenting media to a user. In someembodiments, the waveguide display is incorporated into, e.g., anear-eye-display (NED) as part of an artificial reality system. Thewaveguide display includes a light source assembly, an output waveguide,and a controller. The light source assembly includes one or moreprojectors projecting an image light at least along one dimension. Insome configurations, each of the projectors extend a first angular rangealong a first dimension in the range of −26 degrees to +10 degrees andalong a second dimension in the range of −15 degrees to +15 degrees, anda second angular range along the first dimension in the range of −10degree to +26 degree and along the second dimension in the range of −15degrees to +15 degrees. In one example, the total field-of-view (FOV) is52 degrees along the first dimension and 30 degrees along the seconddimension, and a diagonal FOV is 60 degrees. The output waveguidereceives the image light emitted from at least one of the projectors andoutputs an expanded image light to an eyebox (e.g., a location in spaceoccupied by an eye of a user of the waveguide display) of at least 20 mmby 10 mm. The output waveguide also provides a diagonal FOV of at least60 degrees. The controller controls the scanning of the light sourceassembly to form a two-dimensional image. In some embodiments, thewaveguide display includes a source waveguide that receives the imagelight from the light source assembly along a first dimension and expandthe emitted image light along the first dimension.

Light from the source assembly is in-coupled into the output waveguidethrough an in-coupling area located at one end of the output waveguide.The output waveguide outputs the image light at a location offset fromthe entrance location, and the location/direction of the emitted imagelight is based in part on the orientation of the source assembly. Theoutput waveguide includes a waveguide body with two opposite surfaces.The output waveguide includes at least an input diffraction grating onat least one of the opposite surfaces. In some configurations, the inputdiffraction gratings have substantially the same area along a first anda second dimension, and are separated by a distance along a thirddimension (e.g. on first and second surface, or both on first surfacebut separated with an interfacial layer, or on second surface andseparated with an interfacial layer or both embedded into the waveguidebody but separated with the interfacial layer). The input diffractiongrating in-couples the image light (propagating along an input wavevector) emitted from the light source assembly into the outputwaveguide, and the input diffraction grating has an associated firstgrating vector. In some configurations, the one or more projectors is asingle projector and is located at a center of the input diffractiongrating. In alternate configurations, the light source assembly includesa first projector that projects light into a first input diffractiongrating and a second projector that projects light into a second inputdiffraction grating.

A wave vector of a plane wave is a vector which points in the directionin which the wave propagates (perpendicular to the wave front associatedwith an image light) and its magnitude is inversely proportional to thewavelength of the light, defined to be 2π/λ, where λ is the wavelengthof the light. In this disclosure, only the radial component of the wavevector (parallel to the waveguide surface) is used. For example, a lightfor a projector is associated with a radial wave vector (k_(r0)) whichhas a magnitude of zero for a normal incidence on a surface of theoutput waveguide. Radial component does not change as the light entersor exits the medium (e.g. waveguide). A grating vector is a vector whosedirection is normal to the grating grooves and its vector size isinversely proportional to its pitch. In some configurations, the gratingvector (k_(grating)) is defined to be 2π/p, where p is the pitch of thegrating. Since grating (e.g. surface relief grating) is on the waveguidesurface, the grating vector is always parallel to the surface, and thusit affects only the radial component of the wave vector of the imagelight. Accordingly, the radial component of the wave vector (k_(r)) ofan image light bouncing back and forth in the output waveguide ischanged to k_(r)=k_(r0)±Σk_(grating), where Σk_(grating) is a vector sumof the grating vectors associated with the gratings in a waveguide.

The output waveguide expands the image light in two dimensions. Theoutput waveguide includes a second and third grating (that areassociated with a second and third grating vector, respectively) thattogether direct and decouple the expanded image light from the outputwaveguide, the output expanded image light having a wave vector thatmatches the input wave vector. The output waveguide includes at least afirst grating that receives the image light emitted from at least one ofthe one or more projectors and couples the received image light into thewaveguide body, and the waveguide body expands the received image lightin at least one dimension to transmit a first expanded image light. Eachof the second grating and the third grating expands the first expandedimage light along a different dimension to form a second expanded imagelight, and outputs the second expanded image light to an eyebox. Theinput diffraction grating, the second diffraction grating, and the thirddiffraction grating are designed such that the vector sum of all theirassociated grating vectors is less than a threshold value, and thethreshold value is close to or equal to zero.

The orientation of each source assembly is determined by the controllerbased on the display instructions provided to the light source. Notethat in some embodiments, the image light used in the waveguide displayis polychromatic for each of the primary colors (red, green, and blue)with a finite bandwidth of wavelength. The display acts as atwo-dimensional image projector with an extended pupil over twoorthogonal dimensions.

Embodiments of the invention may include or be implemented inconjunction with an artificial reality system. Artificial reality is aform of reality that has been adjusted in some manner beforepresentation to a user, which may include, e.g., a virtual reality (VR),an augmented reality (AR), a mixed reality (MR), a hybrid reality, orsome combination and/or derivatives thereof. Artificial reality contentmay include completely generated content or generated content combinedwith captured (e.g., real-world) content. The artificial reality contentmay include video, audio, haptic feedback, or some combination thereof,and any of which may be presented in a single channel or in multiplechannels (such as stereo video that produces a three-dimensional effectto the viewer). Additionally, in some embodiments, artificial realitymay also be associated with applications, products, accessories,services, or some combination thereof, that are used to, e.g., createcontent in an artificial reality and/or are otherwise used in (e.g.,perform activities in) an artificial reality. The artificial realitysystem that provides the artificial reality content may be implementedon various platforms, including a head-mounted display (HMD) connectedto a host computer system, a standalone HMD, a mobile device orcomputing system, or any other hardware platform capable of providingartificial reality content to one or more viewers.

FIG. 1 is a diagram of a near-eye-display (NED) 100, in accordance withan embodiment. In some embodiments, the NED 100 may be referred to as ahead-mounted display (HMD). The NED 100 presents media to a user.Examples of media presented by the NED 100 include one or more images,video, audio, or some combination thereof. In some embodiments, audio ispresented via an external device (e.g., speakers and/or headphones) thatreceives audio information from the NED 100, a console (not shown), orboth, and presents audio data based on the audio information. The NED100 is generally configured to operate as a VR NED. However, in someembodiments, the NED 100 may be modified to also operate as an augmentedreality (AR) NED, a mixed reality (MR) NED, or some combination thereof.For example, in some embodiments, the NED 100 may augment views of aphysical, real-world environment with computer-generated elements (e.g.,images, video, sound, etc.).

The NED 100 shown in FIG. 1 includes a frame 105 and a display 110. Theframe 105 is coupled to one or more optical elements which togetherdisplay media to users. In some embodiments, the frame 105 may representa frame of eye-wear glasses. The display 110 is configured for users tosee the content presented by the NED 100. As discussed below inconjunction with FIG. 2, the display 110 includes at least one waveguidedisplay assembly (not shown) for directing one or more image light to aneye of the user. The waveguide display assembly includes, e.g., awaveguide display, a stacked waveguide display, a varifocal waveguidedisplay, or some combination thereof. The stacked waveguide display is apolychromatic display created by stacking waveguide displays whoserespective monochromatic sources are of different colors. The stackedwaveguide display is also a polychromatic display that can be projectedon multiple planes (e.g. multi-planar display). The varifocal waveguidedisplay is a display that can adjust a focal position of image lightemitted from the waveguide display.

FIG. 2 is a cross-section 200 of the NED 100 illustrated in FIG. 1, inaccordance with an embodiment. The display 110 includes at least onewaveguide display assembly 210. An exit pupil 230 is a location wherethe eye 220 is positioned in an eyebox region when the user wears theNED 100. For purposes of illustration, FIG. 2 shows the cross section200 associated with a single eye 220 and a single waveguide displayassembly 210, but in alternative embodiments not shown, anotherwaveguide display assembly which is separate from the waveguide displayassembly 210 shown in FIG. 2, provides image light to an eyebox locatedat an exit pupil of another eye 220 of the user.

The waveguide display assembly 210, as illustrated below in FIG. 2, isconfigured to direct the image light to an eyebox located at an exitpupil 230 of the eye 220. The waveguide display assembly 210 may becomposed of one or more materials (e.g., plastic, glass, etc.) with oneor more refractive indices that effectively minimize the weight andwiden a field of view (hereinafter abbreviated as ‘FOV’) of the NED 100.In alternate configurations, the NED 100 includes one or more opticalelements between the waveguide display assembly 210 and the eye 220. Theoptical elements may act to, e.g., correct aberrations in image lightemitted from the waveguide display assembly 210, magnify image lightemitted from the waveguide display assembly 210, some other opticaladjustment of image light emitted from the waveguide display assembly210, or some combination thereof. The example for optical elements mayinclude an aperture, a Fresnel lens, a convex lens, a concave lens, afilter, or any other suitable optical element that affects image light.

In some embodiments, the waveguide display assembly 210 includes a stackof one or more waveguide displays including, but not restricted to, astacked waveguide display, a varifocal waveguide display, etc. Thestacked waveguide display is a polychromatic display (e.g., ared-green-blue (RGB) display) created by stacking waveguide displayswhose respective monochromatic sources are of different colors. Thestacked waveguide display is also a polychromatic display that can beprojected on multiple planes (e.g. multi-planar colored display). Insome configurations, the stacked waveguide display is a monochromaticdisplay that can be projected on multiple planes (e.g. multi-planarmonochromatic display). The varifocal waveguide display is a displaythat can adjust a focal position of image light emitted from thewaveguide display. In alternate embodiments, the waveguide displayassembly 210 may include the stacked waveguide display and the varifocalwaveguide display.

FIG. 3 illustrates an isometric view of a waveguide display 300, inaccordance with an embodiment. In some embodiments, the waveguidedisplay 300 is a component (e.g., waveguide display assembly 210) of theNED 100. In alternate embodiments, the waveguide display 300 is part ofsome other NED, or other system that directs display image light to aparticular location.

The waveguide display 300 includes a source assembly 310, an outputwaveguide 320, and a controller 330. For purposes of illustration, FIG.3 shows the waveguide display 300 associated with a single eye 220, butin some embodiments, another waveguide display separate (or partiallyseparate) from the waveguide display 300, provides image light toanother eye of the user. In a partially separate system, one or morecomponents may be shared between waveguide displays for each eye.

The source assembly 310 generates image light. The source assembly 310includes an optical source, and an optics system (e.g., as furtherdescribed below with regard to FIG. 4). The source assembly 310generates and outputs image light 355 to a coupling element 350 locatedon a first side 370 of the output waveguide 320. The image light 355propagates along a dimension with an input wave vector as describedbelow with reference to FIG. 5C.

The output waveguide 320 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 320 receives theimage light 355 at one or more coupling elements 350 located on thefirst side 370, and guides the received input image light to decouplingelement 360A. In some embodiments, the coupling element 350 couples theimage light 355 from the source assembly 310 into the output waveguide320. The coupling element 350 may be, e.g., a diffraction grating, aholographic grating, one or more cascaded reflectors, one or moreprismatic surface elements, an array of holographic reflectors, or somecombination thereof. In some configurations, each of the couplingelements 350 have substantially the same area along the X-axis and theY-axis dimension, and are separated by a distance along the Z-axis (e.g.on the first side 370 and the second side 380, or both on the first side370 but separated with an interfacial layer (not shown), or on thesecond side 380 and separated with an interfacial layer or both embeddedinto the waveguide body of the output waveguide 320 but separated withthe interface layer). The coupling element 350 has a first gratingvector. The pitch of the coupling element 350 may be 300-600 nm.

The decoupling element 360A redirects the total internally reflectedimage light from the output waveguide 320 such that it may be decoupledvia the decoupling element 360B. The decoupling element 360A is part of,or affixed to, the first side 370 of the output waveguide 320. Thedecoupling element 360B is part of, or affixed to, the second side 380of the output waveguide 320, such that the decoupling element 360A isopposed to the decoupling element 360B. Opposed elements are opposite toeach other on a waveguide. In some configurations, there may be anoffset between the opposed elements. For example, the offset can be onequarter of the length of an opposed element. The decoupling elements360A and 360B may be, e.g., a diffraction grating, or a holographicgrating, one or more cascaded reflectors, one or more prismatic surfaceelements, an array of holographic reflectors. In some configurations,each of the decoupling elements 360A have substantially the same areaalong the X-axis and the Y-axis dimension, and are separated by adistance along the Z-axis (e.g. on the first side 370 and the secondside 380, or both on the first side 370 but separated with aninterfacial layer (not shown), or on the second side 380 and separatedwith an interfacial layer or both embedded into the waveguide body ofthe output waveguide 320 but separated with the interface layer). Thedecoupling element 360A has an associated second grating vector, and thedecoupling element 360B has an associated third grating vector. Anorientation and position of the image light exiting from the outputwaveguide 320 is controlled by changing an orientation and position ofthe image light 355 entering the coupling element 350. The pitch of thedecoupling element 360A and/or the decoupling element 360B may be300-600 nm. In some configurations, the coupling element 350 couples theimage light into the output waveguide 320 and the image light propagatesalong one dimension. The decoupling element 360A receives image lightfrom the coupling element 350 covering a first portion of the firstangular range emitted by the source assembly 310 and diffracts thereceived image light to another dimension. Note that the received imagelight is expanded in 2D until this state. The decoupling element 360Bdiffracts a 2-D expanded image light toward the eyebox. In alternateconfigurations, the coupling element 350 couples the image light intothe output waveguide 320 and the image light propagates along onedimension. The decoupling element 360B receives image light from thecoupling element 350 covering a first portion of the first angular rangeemitted by the source assembly 310 and diffracts the received imagelight to another dimension. Note that the received image light isexpanded in 2D until this stage. The decoupling element 360A diffracts a2-D expanded image light toward the eyebox.

The coupling element 350, the decoupling element 360A, and thedecoupling element 360B are designed such that a sum of their respectivegrating vectors is less than a threshold value, and the threshold valueis close to or equal to zero. Accordingly, the image light 355 enteringthe output waveguide 320 is propagating in the same direction when it isoutput as image light 340 from the output waveguide 320. Moreover, inalternate embodiments, additional coupling elements and/or de-couplingelements may be added. And so long as the sum of their respectivegrating vectors is less than the threshold value, the image light 355and the image light 340 propagate in the same direction. The location ofthe coupling element 350 relative to the decoupling element 360A and thedecoupling element 360B as shown in FIG. 3 is only an example. In otherconfigurations, the location could be on any other portion of the outputwaveguide 320 (e.g. a top edge of the first side 370, a bottom edge ofthe first side 370). In some embodiments, the waveguide display 300includes a plurality of source assemblies 310 and/or a plurality ofcoupling elements 350 to increase the FOV and/or eyebox further.

The output waveguide 320 includes a waveguide body with the first side370 and a second side 380 that are opposite to each other. In theexample of FIG. 3, the waveguide body includes the two oppositesides—the first side 370 and the second side 380, each of the oppositesides representing a plane along the X-dimension and Y-dimension. Theoutput waveguide 320 may be composed of one or more materials thatfacilitate total internal reflection of the image light 355. The outputwaveguide 320 may be composed of e.g., silicon, plastic, glass, orpolymers, or some combination thereof. The output waveguide 320 has arelatively small form factor. For example, the output waveguide 320 maybe approximately 50 mm wide along X-dimension, 30 mm long alongY-dimension and 0.3-1 mm thick along Z-dimension.

The controller 330 controls the scanning operations of the sourceassembly 310. The controller 330 determines display instructions for thesource assembly 310. The display instructions are generated based atleast on the one or more display instructions generated by thecontroller 330. Display instructions are instructions to render one ormore images. In some embodiments, display instructions may simply be animage file (e.g., bitmap). The display instructions may be receivedfrom, e.g., a console of a system (e.g., as described below inconjunction with FIG. 13). Display instructions are instructions used bythe source assembly 310 to generate image light 340. The displayinstructions may include, e.g., a type of a source of image light (e.g.monochromatic, polychromatic), a scanning rate, an orientation of ascanning apparatus, one or more illumination parameters (described belowwith reference to FIG. 4), or some combination thereof. The controller330 includes a combination of hardware, software, and/or firmware notshown here so as not to obscure other aspects of the disclosure.

In alternate configurations (not shown), the output waveguide 320includes the coupling element 350 on the first side 370 and a secondcoupling element (not shown here) on the second side 380. The couplingelement 350 receives an image light 355 from the source assembly 310.The coupling element on the second side 380 receives an image light fromthe source assembly 310 and/or a different source assembly. Thecontroller 330 determines the display instructions for the sourceassembly 310 based at least on the one or more display instructions.

In alternate configurations, the output waveguide 320 may be orientedsuch that the source assembly 310 generates the image light 355propagating along an input wave vector in the Z-dimension. The outputwaveguide 320 outputs the image light 340 propagating along an outputwave vector that matches the input wave vector. In some configurations,the image light 340 is a monochromatic image light that can be projectedon multiple planes (e.g. multi-planar monochromatic display). Inalternate configurations, the image light 340 is a polychromatic imagelight that can be projected on multiple planes (e.g. multi-planarpolychromatic display).

In some embodiments, the output waveguide 320 outputs the expanded imagelight 340 to the user's eye 220 with a very large FOV. For example, theexpanded image light 340 provided to the user's eye 220 with a diagonalFOV (in x and y) of at least 60 degrees. The output waveguide 320 isconfigured to provide an eyebox of with a length of at least 20 mm and awidth of at least 10 mm. Generally, the horizontal FOV is larger thanthe vertical FOV. If the aspect ratio is 16:9, the product of thehorizontal FOV and the vertical FOV will be ˜52×30 degrees whosediagonal FOV is 60 degrees for instance.

FIG. 4 illustrates a cross section 400 of the waveguide display 300, inaccordance with an embodiment. The cross section 400 of the waveguidedisplay 300 includes the source assembly 310 and an output waveguide420.

The source assembly 310 generates light in accordance with displayinstructions from the controller 330. The source assembly 310 includes asource 410, and an optics system 415. The source 410 is a source oflight that generates at least a coherent or partially coherent imagelight. The source 410 may be, e.g., laser diode, a vertical cavitysurface emitting laser, a light emitting diode, a tunable laser, aMicroLED, a superluminous LED (SLED), or some other light source thatemits coherent or partially coherent light. The source 410 emits lightin a visible band (e.g., from about 390 nm to 700 nm), and it may emitlight that is continuous or pulsed. In some embodiments, the source 410may be a laser that emits light at a particular wavelength (e.g., 532nanometers). The source 410 emits light in accordance with one or moreillumination parameters received from the controller 330. Anillumination parameter is an instruction used by the source 410 togenerate light. An illumination parameter may include, e.g., restrictionof input wave vector for total internal reflection, restriction of inputwave vector for maximum angle, source wavelength, pulse rate, pulseamplitude, beam type (continuous or pulsed), other parameter(s) thataffect the emitted light, or some combination thereof.

The optics system 415 includes one or more optical components thatcondition the light from the source 410. Conditioning light from thesource 410 may include, e.g., expanding, collimating, adjustingorientation in accordance with instructions from the controller 330,some other adjustment of the light, or some combination thereof. The oneor more optical components may include, e.g., lenses, liquid lens,mirrors, apertures, gratings, or some combination thereof. In someconfigurations, the optics system 415 includes liquid lens with aplurality of electrodes that allows scanning a beam of light with athreshold value of scanning angle in order to shift the beam of light toa region outside the liquid lens. In an alternate configuration, theoptics system 415 includes a voice coil motor that performs onedimensional scanning of the light to a threshold value of scanningangle. The voice coil motor performs a movement of one or more lens tochange a direction of the light outside the one or more lens in order tofill in the gaps between each of the multiple lines scanned. Lightemitted from the optics system 415 (and also the source assembly 310) isreferred to as image light 455. The optics system 415 outputs the imagelight 455 at a particular orientation (in accordance with the displayinstructions) toward the output waveguide 420. The image light 455propagates along an input wave vector such that the restrictions forboth total internal reflection and maximum angle of propagation are met.

The output waveguide 420 receives the image light 455. The couplingelement 450 at the first side 470 couples the image light 455 from thesource assembly 310 into the output waveguide 420. In embodiments wherethe coupling element 450 is diffraction grating, the pitch of thediffraction grating is chosen such that total internal reflectionoccurs, and the image light 455 propagates internally toward thedecoupling element 460A. For example, the pitch of the coupling element450 may be in the range of 300 nm to 600 nm. In alternate embodiments,the coupling element 450 is located at the second side 480 of the outputwaveguide 420.

The decoupling element 460A redirects the image light 455 toward thedecoupling element 460B for decoupling from the output waveguide 420. Inembodiments where the decoupling element 460A and 460B is a diffractiongrating, the pitch of the diffraction grating is chosen to causeincident image light 455 to exit the output waveguide 420 at a specificangle of inclination to the surface of the output waveguide 420. Anorientation of the image light exiting from the output waveguide 420 maybe altered by varying the orientation of the image light exiting thesource assembly 310, varying an orientation of the source assembly 310,or some combination thereof. For example, the pitch of the diffractiongrating may be in the range of 300 nm to 600 nm. The coupling element450, the decoupling element 460A and the decoupling element 460B aredesigned such that a sum of their respective grating vectors is lessthan a threshold value, and the threshold value is close to or equal tozero.

In some configurations, the first decoupling element 460A receives theimage light 455 from the coupling element 450 after total internalreflection in the waveguide body and transmits an expanded image lightto the second decoupling element 460B at the second side 480. The seconddecoupling element 460B decouples the expanded image light 440 from thesecond side 480 of the output waveguide 420 to the user's eye 220. Thefirst decoupling element 460A and the second decoupling element 460B arestructurally similar. In alternate configurations, the second decouplingelement 460B receives the image light 455 after total internalreflection in the waveguide body and transmits an expanded image lightfrom the first decoupling element 460A on the first side 470.

The image light 440 exiting the output waveguide 420 is expanded atleast along two dimension (e.g., may be elongated along X-dimension).The image light 440 couples to the human eye 220. The image light 440exits the output waveguide 420 such that a sum of the respective gratingvectors of each of the coupling element 450, the decoupling element460A, and the decoupling element 460B is less than a threshold value,and the threshold value is close to or equal to zero. An exact thresholdvalue is going to be system specific, however, it should be small enoughto not degrade image resolution beyond acceptable standards (if non-zerodispersion occurs and resolution starts to drop). In someconfigurations, the image light 440 propagates along wave vectors alongat least one of X-dimension, Y-dimension, and Z-dimension.

In alternate embodiments, the image light 440 exits the output waveguide420 via the decoupling element 460A. Note the decoupling elements 460Aand 460B are larger than the coupling element 450, as the image light440 is provided to an eyebox located at an exit pupil of the waveguidedisplay.

In another embodiment, the waveguide display includes two or moredecoupling elements. For example, the decoupling element 460A mayinclude multiple decoupling elements located side by side with anoffset. In another example, the decoupling element 460A may includemultiple decoupling elements stacked together to create atwo-dimensional decoupling element.

The controller 330 controls the source assembly 310 by providing displayinstructions to the source assembly 310. The display instructions causethe source assembly 310 to render light such that image light exitingthe decoupling element 460A of the output waveguide 420 scans out one ormore 2D images. For example, the display instructions may cause thesource assembly 310 (via adjustments to optical elements in the opticssystem 415) to scan out an image in accordance with a scan pattern(e.g., raster, interlaced, etc.). The display instructions control anintensity of light emitted from the source 410, and the optics system415 scans out the image by rapidly adjusting orientation of the emittedlight. If done fast enough, a human eye integrates the scanned patterninto a single 2D image.

A collimated beam of image light has one or more physical properties,including, but not restricted to, wavelength, luminous intensity, flux,etc. The wavelength of collimated beam of image light from a sourceassembly strongly impacts, among several other parameters, the FOV ofthe NED 100. The FOV would be very small in cases where a sourceassembly emits image light across an entire visible band of image light.However, the waveguide display 300 has a relatively large FOV as thewaveguide display includes a mono-chromatic source in the example shownin FIG. 4. Accordingly, to generate a polychromatic display that has alarge FOV, one or more monochromatic waveguide displays (with one ormore image light at different wavelengths) are stacked to generate asingle polychromatic stacked waveguide display.

The waveguide display of FIG. 4 shows an example with a single outputwaveguide 420 receiving a monochromatic beam of image light 455 from thesource assembly 310. In alternate embodiments, the waveguide display 300includes a plurality of source assemblies 310 and a plurality of outputwaveguides 420. Each of the source assemblies 310 emits a monochromaticimage light of a specific band of wavelength corresponding to one of theprimary colors (red, green, and blue). Each of the output waveguides 420may be stacked together with a distance of separation to output anexpanded image light 440 that is multi-colored. The output waveguidesare stacked such that image light (e.g., 440) from each of the stackedwaveguides occupies a same area of the exit pupil of the stackedwaveguide display. For example, the output waveguides may be stackedsuch that decoupling elements from adjacent optical waveguides are linedup and light from a rear output waveguide would pass through thedecoupling element of the waveguide adjacent to and in front of the rearoutput waveguide. In some configurations, the expanded image light 440can couple to the user's eye 220 as a multi-planar display. For example,the expanded image light 440 may include a display along at least twodifferent depths along the Z-dimension.

In alternate embodiments, the location of the coupling element 450 canbe located on the second side 480. In some configurations, the waveguidedisplay of FIG. 4 may perform a scanning operation of the source 410inside the source assembly 310 to form a line image. The location of thecoupling element 450 shown in FIG. 4 is only an example, and severalother arrangements are apparent to one of ordinary skill in the art.

FIG. 5A illustrates an isometric view 500 of a first design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theisometric view 500 includes the source assembly 510 and an outputwaveguide 520. The source assembly 510 generates image light, andprovides the image light to the output waveguide 520.

The output waveguide 520 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 520 receives imagelight from the source assembly 510 at one or more coupling elements 550,and guides the received input image light to the decoupling element560A. The coupling element 550 couples the image light from the sourceassembly 510 into the output waveguide 520. The coupling element 550 maybe, e.g., a diffraction grating, a holographic grating, or somecombination thereof. The coupling element 550 has a first gratingvector. The pitch of the coupling element 550 may be 300-600 nm.

In one configuration, the first design of the waveguide display providesa horizontal field of view of 51.0 degrees, a vertical field of view of31.9 degrees, and a diagonal field of view of 60.1 degrees. In anotherconfiguration, the coupling element 550 includes a pitch in the range of0.3 to 0.6 micron, and the decoupling elements 560A and 560B include apitch in the range of 0.3 to 0.6 micron.

FIG. 5B illustrates a top view 505 of the first design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The top view505 includes the coupling element 550, the decoupling element 560A, andthe decoupling element 560B of the output waveguide 520.

FIG. 5C illustrates an example path 515 of grating vectors associatedwith a plurality of diffraction gratings of the first design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theexample path 515 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 550, the firstdecoupling element 560A, and the second decoupling element 560B that theimage light meets. The grating vectors are just added to change the pathof the wave vector. In the example path 515, image light from the sourceassembly (not shown here) is associated with a projected radial wavevector (not shown). The image light is coupled into the output waveguide520 via the coupling element 550 associated with an input grating vector(not shown). The in-coupled light is then diffracted by the firstdecoupling element 560A associated with a first grating vector (notshown). The light is then diffracted (and out coupled from the outputwaveguide 520) by the second decoupling element 560B associated with asecond grating vector (not shown). In one embodiment, the example path515 includes a summation point 565A. The summation of the input gratingvector, the first grating vector, and the second grating vector at thesummation point 565A is zero. In a second embodiment, the example path515 includes a summation point 565B. The summation of the input gratingvector, the first grating vector, and the second grating vector at thesummation point 565B is zero.

FIG. 5D illustrates an isometric view 525 of a second design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theisometric view 525 includes the source assembly 510 and an outputwaveguide 522. The source assembly 510 generates image light, andprovides the image light to the output waveguide 522.

The output waveguide 522 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 522 receives imagelight from the source assembly 510 at one or more coupling elements 552,and guides the received input image light to the decoupling element 562Aor the decoupling element 562B. The coupling element 552 couples theimage light from the source assembly 510 into the output waveguide 522.The coupling element 552 may be, e.g., a diffraction grating, aholographic grating, or some combination thereof. The coupling element552 has a first grating vector. The pitch of the coupling element 552may be 300-600 nm.

FIG. 5E illustrates a top view 530 of the second design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The top view530 includes the coupling element 552, the decoupling element 562A, andthe decoupling element 562B of the output waveguide 522.

FIG. 5F illustrates an example path 535 of grating vectors associatedwith a plurality of diffraction gratings of the second design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theexample path 535 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 552, the firstdecoupling element 562A, and the second decoupling element 562B that theimage light meets. The grating vectors are just added to change the pathof the wave vector. In the example path 535, image light from the sourceassembly (not shown here) is associated with a projected radial wavevector (not shown). The image light is coupled into the output waveguide522 via the coupling element 552 associated with an input grating vector(not shown). The in-coupled light is then diffracted by the firstdecoupling element 562A associated with a first grating vector (notshown). The light is then diffracted (and out coupled from the outputwaveguide 522) by the second decoupling element 562B associated with asecond grating vector (not shown). In alternate configurations, theimage light is coupled into the output waveguide 522 via the couplingelement 552 associated with an input grating vector (not shown). Thein-coupled light is then diffracted by the second decoupling element562B associated with a first grating vector (not shown). The light isthen diffracted (and out coupled from the output waveguide 522) by thefirst decoupling element 562A associated with a second grating vector(not shown). In one embodiment, the example path 535 includes asummation point 565D. The summation point 565D corresponds to the sum ofthe k-vectors in the order corresponding to: a grating vector associatedwith the coupling element 552, a grating vector associated with thedecoupling element 562A, the grating vector associated with thedecoupling element 562A, and the grating vector associated with thedecoupling element 562B. In a second embodiment, the example path 535includes a summation point 565E. The summation point 565E corresponds tothe sum of the k-vectors in the order corresponding to: the gratingvector associated with the coupling element 552, a grating vectorassociated with the decoupling element 562A, the grating vectorassociated with the decoupling element 562B, and the grating vectorassociated with the decoupling element 562A. In a third embodiment, theexample path 535 includes a summation point 565F. The summation point565F corresponds to the sum of the k-vectors in the order correspondingto: a grating vector associated with the coupling element 552, a gratingvector associated with the decoupling element 562B, the grating vectorassociated with the decoupling element 562B, and the grating vectorassociated with the decoupling element 562A. In a fourth embodiment, theexample path 535 includes a summation point 565G. The summation point565G corresponds to the sum of the k-vectors in the order correspondingto: a grating vector associated with the coupling element 552, a gratingvector associated with the decoupling element 562B, the grating vectorassociated with the decoupling element 562A, and the grating vectorassociated with the decoupling element 562B.

FIG. 5G illustrates an isometric view of a third design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The isometricview 540 includes the source assembly 510 and an output waveguide 524.The source assembly 510 generates image light, and provides the imagelight to the output waveguide 524.

The output waveguide 524 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 524 receives imagelight from the source assembly 510 at one or more coupling elements 554,and guides the received input image light to the decoupling element564A. The coupling element 554 couples the image light from the sourceassembly 510 into the output waveguide 524. The coupling element 554 maybe, e.g., a diffraction grating, a holographic grating, or somecombination thereof. The coupling element 554 has a first gratingvector. The pitch of the coupling element 554 may be 300-600 nm.

FIG. 5H illustrates a top view 545 of the third design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The top view545 includes the coupling element 554, the decoupling element 564A, andthe decoupling element 564B of the output waveguide 524.

FIG. 5I illustrates an example path 551 of grating vectors associatedwith a plurality of diffraction gratings of the third design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theexample path 551 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 554, the firstdecoupling element 564A, and the second decoupling element 564B that theimage light meets. The grating vectors are just added to change the pathof the wave vector. In the example path 551, image light from the sourceassembly (not shown here) is associated with a projected radial wavevector (not shown). The image light is coupled into the output waveguide524 via the coupling element 554 associated with an input grating vector(not shown). The in-coupled light is then diffracted by the firstdecoupling element 564A associated with a first grating vector (notshown). The light is then diffracted (and out coupled from the outputwaveguide 524) by the second decoupling element 564B associated with asecond grating vector (not shown). In one embodiment, the example path551 includes a summation point 565H. The summation of the input gratingvector, the first grating vector, and the second grating vector at thesummation point 565H is zero. In a second embodiment, the example path551 includes a summation point 565I. The summation point 565Icorresponds to the sum of the k-vectors in the order corresponding to: agrating vector associated with the coupling element 554, a gratingvector associated with the decoupling element 564B, and the gratingvector associated with the decoupling element 564A. The summation of theinput grating vector, the first grating vector, and the second gratingvector at the summation point 565I is zero.

FIG. 5J illustrates an isometric view 560 of a fourth design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theisometric view 560 includes the source assembly 510 and an outputwaveguide 526. The source assembly 510 generates image light, andprovides the image light to the output waveguide 526.

The output waveguide 526 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 526 receives imagelight from the source assembly 510 at one or more coupling elements 556,and guides the received input image light to the decoupling element566A. The coupling element 556 couples the image light from the sourceassembly 510 into the output waveguide 526. The coupling element 556 maybe, e.g., a diffraction grating, a holographic grating, or somecombination thereof. The coupling element 556 has a first gratingvector. The pitch of the coupling element 556 may be 300-600 nm.

FIG. 5K illustrates a top view 565 of the fourth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The top view565 includes the coupling element 556, the decoupling element 566A, andthe decoupling element 566B of the output waveguide 526.

FIG. 5L illustrates an example path 570 of grating vectors associatedwith a plurality of diffraction gratings of the fourth design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theexample path 570 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 556, the firstdecoupling element 566A, and the second decoupling element 566B that theimage light meets. The grating vectors are just added to change the pathof the wave vector. In the example path 570, image light from the sourceassembly (not shown here) is associated with a projected radial wavevector (not shown). The image light is coupled into the output waveguide526 via the coupling element 556 associated with an input grating vector(not shown). The in-coupled light is then diffracted by the firstdecoupling element 566A associated with a first grating vector (notshown). The light is then diffracted (and out coupled from the outputwaveguide 526) by the second decoupling element 566B associated with asecond grating vector (not shown). In one embodiment, the example path570 includes a summation point 565J. The summation of the input gratingvector, the first grating vector, and the second grating vector at thesummation point 565J is zero. In a second embodiment, the example path570 includes a summation point 565K. The summation point 565Kcorresponds to the sum of the k-vectors in the order corresponding to: agrating vector associated with the coupling element 556, a gratingvector associated with the decoupling element 566B, and the gratingvector associated with the decoupling element 566A. The summation of theinput grating vector, the first grating vector, and the second gratingvector at the summation point 565K is zero.

FIG. 5M illustrates an isometric view 575 of a fifth design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theisometric view 575 includes the source assembly 510 and an outputwaveguide 528. The source assembly 510 generates image light, andprovides the image light to the output waveguide 528.

The output waveguide 528 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 528 receives imagelight from the source assembly 510 at the first coupling element 558Aand the second coupling element 558B, and guides the received inputimage light to the decoupling element 568A. The first coupling element558A and the second coupling element 558B couple the image light fromthe source assembly 510 into the output waveguide 528. The role of thefirst coupling element 558A and the second coupling element 558B is tosplit the image light from the source assembly 510 horizontally inadvance (before the in-coupled image light reaches the decouplingelement 568A or 568B). The configuration shown in the example of FIG.5M, among several other merits, helps to reduce the lateral surface areaof the output waveguide 528, and achieve a substantially lower formfactor for the output waveguide 528.

The coupling element 558A and the coupling element 558B may be, e.g., adiffraction grating, a holographic grating, or some combination thereof.The coupling element 558A and the coupling element 558B has a firstgrating vector. The pitch of the coupling element 558A and the couplingelement 558B may be 300-600 nm.

FIG. 5N illustrates a top view 580 of the fifth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The top view580 includes the first coupling element 558A, the second couplingelement 558B, the decoupling element 568A, and the decoupling element568B of the output waveguide 528. The example path 585 is a path of awave vector of the image light that is affected by the grating vectorsof the first coupling element 558A, the second coupling element 558B,the first decoupling element 568A, and the second decoupling element568B that the image light meets. The grating vectors are just added tochange the path of the wave vector. In the example path 585, image lightfrom the source assembly (not shown here) is associated with a projectedradial wave vector (not shown). The image light is coupled into theoutput waveguide 528 via the first coupling element 558A and the secondcoupling element 558B associated with an input grating vector (notshown). The in-coupled light is then diffracted by the first decouplingelement 568A associated with a first grating vector (not shown). Thelight is then diffracted (and out coupled from the output waveguide 528)by the second decoupling element 568B associated with a second gratingvector (not shown). In one embodiment, the example path 585 includes asummation point 565P. The summation of the input grating vector, thefirst grating vector, and the second grating vector at the summationpoint 565P is zero. In a second embodiment, the example path 585includes a summation point 565Q. The summation point 565Q corresponds tothe sum of the k-vectors in the order corresponding to: a grating vectorassociated with the first coupling element 558A, the second couplingelement 558B, a grating vector associated with the decoupling element568B, and the grating vector associated with the decoupling element568A. The summation of the input grating vector, the first gratingvector, and the second grating vector at the summation point 565Q iszero.

FIG. 5O illustrates an example path 585 of grating vectors associatedwith a plurality of diffraction gratings of the fifth design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theexample path 585 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 558A, the firstdecoupling element 566A, and the second decoupling element 566B that theimage light meets. The grating vectors are just added to change the pathof the wave vector. In the example path 570, image light from the sourceassembly (not shown here) is associated with a projected radial wavevector (not shown). The image light is coupled into the output waveguide526 via the coupling element 556 associated with an input grating vector(not shown). The in-coupled light is then diffracted by the firstdecoupling element 566A associated with a first grating vector (notshown). The light is then diffracted (and out coupled from the outputwaveguide 526) by the second decoupling element 566B associated with asecond grating vector (not shown). In one embodiment, the example path570 includes a summation point 565J. The summation of the input gratingvector, the first grating vector, and the second grating vector at thesummation point 565J is zero. In a second embodiment, the example path570 includes a summation point 565K. The summation point 565Kcorresponds to the sum of the k-vectors in the order corresponding to: agrating vector associated with the coupling element 556, a gratingvector associated with the decoupling element 566B, and the gratingvector associated with the decoupling element 566A. The summation of theinput grating vector, the first grating vector, and the second gratingvector at the summation point 565K is zero.

FIG. 6A illustrates an isometric view of a sixth design of the waveguidedisplay 600 shown in FIG. 4, in accordance with an embodiment. Thewaveguide display 600 includes the source assembly 610, a sourcewaveguide 615A, and an output waveguide 620.

The source waveguide 615A is an optical waveguide. The source waveguide615A receives the image light from the source assembly 610 and outputsan image light (not shown) to an output waveguide 620. The image lightfrom the source waveguide 615A propagates along a dimension with aninput wave vector as described below with reference to FIG. 6C.

The output waveguide 620 is an optical waveguide. The output waveguide620 includes a coupling element 650A, a decoupling element 660A and adecoupling element 660B.

FIG. 6B illustrates a top view 670 of the sixth design of the waveguidedisplay shown in FIG. 4, in accordance with an embodiment. The top view670 includes the source assembly 610, the source waveguide 615A, and theoutput waveguide 620.

FIG. 6C illustrates an example path 680 of grating vectors associatedwith a plurality of diffraction gratings of the sixth design of thewaveguide display shown in FIG. 4, in accordance with an embodiment. Theexample path 680 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 650A, the firstdecoupling element 660A, and the second decoupling element 660B that theimage light meets. The grating vectors are just added to change the pathof the wave vector. In the example path 680, image light from the sourceassembly 610 is associated with a projected radial wave vector (notshown). The image light is coupled into the output waveguide 620 via thecoupling element 650A associated with an input grating vector (notshown). The in-coupled light is then diffracted by the first decouplingelement 660A associated with a first grating vector (not shown). Thelight is then diffracted (and out coupled from the output waveguide) bythe second decoupling element 660B associated with a second gratingvector (not shown). In one embodiment, the example path 680 includes afirst summation point 655C, a second summation point 665C, and a thirdsummation point 665D. Note that the summation of the projected radialwave vector at the first summation point 655C is zero.

In a different embodiment, the example path 680 includes a summationpoint 655D, a summation point 665E, and a summation point 665F. Thesummation point 655D is an embodiment of the first summation point 655C.The summation point 665E is an embodiment of the second summation point665C. The summation point 665F is an embodiment of the third summationpoint 655D. Note that the summation point 655C and the summation point655D occur in the source waveguide 615A, while the summation point 665C,the summation point 665D, the summation point 665E, and the summationpoint 665F occur in the output waveguide 620.

The coupling element 650A, the first decoupling element 660A, and thesecond decoupling element 660B, are diffraction gratings whose gratingvectors sum to a value that is less than a threshold value, and thethreshold value is close to or equal to zero. In this example, a zerosummation occurs, as the vector path returns to its origination point.With the occurrence of the zero summation, the image light exits theoutput waveguide 620 with the same angle as the incident angle from thesource assembly 610 since the remaining radial wave vector is associatedwith the FOV of the waveguide display.

FIG. 7 illustrates an isometric view of a waveguide display 700 with twosource assemblies, in accordance with an embodiment. The waveguidedisplay 700 includes a first source assembly 710A, a second sourceassembly 710B, an output waveguide 720 and the controller 330.

The first source assembly 710A generates and outputs an image light 755Ato the first coupling element 750A. The second source assembly 710Bgenerates and outputs an image light 755B to the second coupling element750B. Each of the image light 755A and the image light 755B is anembodiment of the image light 355 of FIG. 3. The controller 330 sendsdisplay instructions to each of the first source assembly 710A and thesecond source assembly 710B.

In some embodiments, the first source assembly 710A and the secondsource assembly 710B are located with a threshold value of distance ofseparation along the X-dimension. In alternate embodiments, the firstsource assembly 710A and the second source assembly 710B are locatedwith a threshold value of distance of separation along the Y-dimension.Example positions of the first source assembly 710A and 710B are alsodiscussed below with regard to FIGS. 9A, 10A, and 11A.

The output waveguide 720 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 720 receives theimage light 755A at the coupling element 750A and the image light 755Bat the coupling element 750B, and guides the received input image lightto the decoupling element 760A. In some embodiments, the couplingelement 750A couples the image light 755A from the first source assembly710A into the output waveguide 720. The coupling element 750A may be,e.g., a diffraction grating, a holographic grating, one or more cascadedreflectors, one or more prismatic surface elements, an array ofholographic reflectors, or some combination thereof. The couplingelement 750A has a first grating vector. The pitch of the couplingelement 750A may be 300-600 nm. The coupling element 750A may be 2 mmwide and 2 mm thick.

The coupling element 750A at the first side 770 couples the image light755A from the first source assembly 710A into the output waveguide 720.In embodiments where the coupling element 750A is diffraction grating,the pitch of the diffraction grating is chosen such that total internalreflection occurs, and the image light 755A propagates internally towardthe decoupling element 760A. For example, the pitch of the couplingelement 750A may be in the range of 300 nm to 600 nm. In alternateembodiments, the coupling element 750A is located at the second side 780of the output waveguide 720. The coupling element 750B is an embodimentof the coupling element 750A. The image light 755B is an embodiment ofthe image light 755A.

The decoupling element 760A redirects the image light 755A toward thedecoupling element 760B for decoupling from the output waveguide 720. Inembodiments where the decoupling element 760A is a diffraction grating,the pitch of the diffraction grating is chosen to cause incident imagelight 755A to exit the output waveguide 720 at a specific angle ofinclination to the surface of the output waveguide 720. An orientationof the image light exiting from the output waveguide 720 may be alteredby varying the orientation of the image light exiting the first sourceassembly 710A, varying an orientation of the first source assembly 710A,or some combination thereof. For example, the pitch of the diffractiongrating may be in the range of 300 nm to 600 nm, and the size of thediffraction grating may be 30 mm by 25 mm. Both the coupling element 750and the decoupling element 760A are designed such that a sum of theirrespective grating vectors is less than a threshold value, and thethreshold value is close to or equal to zero. In some configurations,the coupling elements 750A and 750B couple the image light into theoutput waveguide 720 and the image light propagates along one dimension.The decoupling element 760A receives image light from the couplingelements 750A and 750B covering a first portion of the first angularrange emitted by the source assemblies 710A and 710B and diffracts thereceived image light to another dimension. Note that the received imagelight is expanded in 2D until this stage. The decoupling element 760Bdiffracts a 2-D expanded image light toward the eyebox. In alternateconfigurations, the coupling elements 750A and 750B couple the imagelight into the output waveguide 720 and the image light propagates alongone dimension. The decoupling element 760B receives image light from thecoupling elements 750A and 750B covering a first portion of the firstangular range emitted by the first source assembly 710A and the secondsource assembly 710B, and diffracts the received image light to anotherdimension. Note that the received image light is expanded in 2D untilthis state. The decoupling element 760A diffracts a 2-D expanded imagelight toward the eyebox.

The image light 740 exiting the output waveguide 720 is expanded atleast along two dimensions (e.g., may be elongated along X-dimension).The image light 740 couples to the human eye 220. The image light 740exits the output waveguide 720 such that a sum of the respective gratingvectors of each of the coupling element 750, the decoupling element760A, and the decoupling element 760B is less than a threshold value,and the threshold value is close to or equal to zero. An exact thresholdvalue is going to be system specific, however, it should be small enoughto not degrade image resolution beyond acceptable standards (if non-zerodispersion occurs and resolution starts to drop). In someconfigurations, the image light 740 propagates along wave vectors alongat least one of X-dimension, Y-dimension, and Z-dimension.

In alternate embodiments, the image light 740 exits the output waveguide720 via the decoupling element 760A. Note the decoupling elements 760Aand 760B are larger than the coupling element 750A, as the image light740 is provided to an eyebox located at an exit pupil of the waveguidedisplay 700.

In another embodiment, the waveguide display 700 includes two or moredecoupling elements. For example, the decoupling element 760A mayinclude multiple decoupling elements located side by side with anoffset. In another example, the decoupling element 760A may includemultiple decoupling elements stacked together to create atwo-dimensional decoupling element.

The controller 330 controls the first source assembly 710A and thesecond source assembly 710B by providing display instructions to each ofthe first source assembly 710A and the second source assembly 710B. Thedisplay instructions cause the first source assembly 710A and the secondsource assembly 710B to render light such that image light exiting thedecoupling element 760A of the output waveguide 720 scans out one ormore 2D images. For example, the display instructions may cause thefirst source assembly 710A and the second source assembly 710B (viaadjustments to optical elements in the optics system 820) to scan out animage in accordance with a scan pattern (e.g., raster, interlaced,etc.).

FIG. 8 illustrates a cross section 800 of the waveguide displayincluding two source assemblies, a portion of two decoupling elements,and two coupling elements, in accordance with an embodiment. The crosssection 800 includes the first source assembly 710A, the second sourceassembly 710B, and a portion of the output waveguide 720 of FIG. 7.

Each of the first source assembly 710A and the second source assembly710B generates light in accordance with display instructions from thecontroller 330. The first source assembly 710A includes the source 810,and the optics system 820, as described above in conjunction with FIG.4. The second source assembly 810B is an embodiment of the first sourceassembly 810A.

The output waveguide 720 is an optical waveguide that outputs an imagelight 840 to an eye 220 of a user. The output waveguide 720 receives theimage light 855A at the coupling element 850A and the image light 855Bat the coupling element 850B located on a first side 870, and guides thereceived input image light to a portion of a decoupling element 860A. Insome embodiments, the coupling element 850A couples the image light 855Afrom the first source assembly 810A into the output waveguide 720. Thecoupling element 850A may be, e.g., a diffraction grating, a holographicgrating, or some combination thereof. The coupling element 850A has afirst grating vector. The pitch of the coupling element 850A may be300-600 nm.

The portion of the decoupling element 860A redirects the totalinternally reflected image light from the output waveguide 720 such thatit may be decoupled via a portion of the decoupling element 860B. Theportion of the decoupling element 860A is part of, or affixed to, thefirst side 870 of the output waveguide 720. The decoupling element 860Bis part of, or affixed to, a second side 880 of the output waveguide720, such that the portion of the decoupling element 860A is opposed tothe decoupling element 860B. Opposed elements are opposite to each otheron a waveguide.

The coupling element 850A, the coupling element 850B, the portion of thedecoupling element 860A, and the portion of the decoupling element 860Bare designed such that a sum of their respective grating vectors is lessthan a threshold value, and the threshold value is close to or equal tozero. Accordingly, the image light 855A and the image light 855Bentering the output waveguide 720 is propagating in the same directionwhen it is output as image light 840 from a portion of the decouplingelement 860B of the output waveguide 720. Moreover, in alternateembodiments, additional coupling elements and/or de-coupling elementsmay be added. And so long as the sum of their respective grating vectorsis less than the threshold value, the image light 855A, the image light855B and the image light 840 propagate in the same direction. In someembodiments, the waveguide display includes a plurality of the firstsource assemblies 710A, a plurality of the second source assemblies 710Band/or a plurality of the coupling elements 850A and the couplingelements 850B to increase the FOV further.

The controller 330 controls the first source assembly 710A and thesecond source assembly 710B by providing display instructions to each ofthe first source assembly 710A and the second source assembly 710B. Thedisplay instructions cause the first source assembly 710A and the secondsource assembly 710B to render light such that image light exiting thedecoupling element 860B of the output waveguide 720 scans out one ormore 2D images. The display instructions control an intensity of lightemitted from the source 810, and the optics system 820 scans out theimage by rapidly adjusting orientation of the emitted light. If donefast enough, a human eye integrates the scanned pattern into a single 2Dimage.

FIG. 9A illustrates an isometric view 900 of a seventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theisometric view 900 includes the first source assembly 910A, the secondsource assembly 910B and an output waveguide 920.

Each of the first source assembly 910A and the second source assembly910B is a set of optical components that perform a generation andconditioning of an image light. The first source assembly 910A outputsan image light (not shown) to the output waveguide 920. The secondsource assembly 910B outputs an image light (not shown) to the outputwaveguide 920.

The output waveguide 920 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 920 receives animage light (not shown) at the coupling element 950A and the couplingelement 950B, and guides the received input image light to thedecoupling element 960A. In some embodiments, the coupling element 950Aand the coupling element 950B couple the image light from the firstsource assembly 910A and the second source assembly 910B into the outputwaveguide 920. The coupling element 950A may be, e.g., a diffractiongrating, a holographic grating, or some combination thereof. Thecoupling element 950A has a first grating vector. The pitch of thecoupling element 950A may be 300-600 nm. As shown in FIG. 9A, the outputwaveguide 920 includes the first source assembly 910A that projectslight into the coupling element 950A, and the second source assembly910B that projects light into the coupling element 950B, and thecoupling element 950A and the coupling element 950B are on the samesurface of the output waveguide 920, and both the coupling element 950Aand the coupling element 950B are located adjacent to a same side alongthe X-dimension of the decoupling element 960A. In one configuration,the seventh design of the waveguide display provides a horizontal fieldof view of 65.0 degrees, a vertical field of view of 30.5 degrees, and adiagonal field of view of 71.8 degrees. In another configuration, thecoupling element 950A and the coupling element 950B include a pitch inthe range of 300 nm to 600 nm, and the decoupling elements 960A and 960Binclude a pitch in the range of 300 nm to 600 nm. In yet anotherconfiguration, the first source assembly 910A and the second sourceassembly 910B include a distance of separation of at least 20 mm.

FIG. 9B illustrates a top view 905 of the seventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Thetop view 905 includes the coupling element 950A, the coupling element950B, the decoupling element 960A, and the decoupling element 960B ofthe output waveguide 920.

FIG. 9C illustrates an example path 915 of grating vectors associatedwith a plurality of diffraction gratings of the seventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theexample path 915 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 950A, thecoupling element 950B, the first decoupling element 960A, and the seconddecoupling element 960B that the image light meets. The grating vectorsare just added to change the path of the wave vector. In the examplepath 915, image light from each of the source assemblies (not shownhere) is associated with a respective projected radial wave vector (notshown). The image light is coupled into the output waveguide 920 via thecoupling element 950A and the coupling element 950B associated with arespective input grating vector (not shown). The in-coupled light isthen diffracted by the first decoupling element 960A associated with afirst grating vector (not shown). The light is then diffracted (and outcoupled from the output waveguide 920) by the second decoupling element960B associated with a second grating vector (not shown). In oneembodiment, the example path 915 includes a summation point 965A. Thesummation of the input grating vector, the first grating vector, and thesecond grating vector at the summation point 965A is zero. In a secondembodiment, the example path 915 includes a summation point 965B. Thesummation of the input grating vector, the first grating vector, and thesecond grating vector at the summation point 965B is zero. In someconfigurations, the example path 915 includes at least two of the inputwave vector, the first grating vector, and the second grating vectorintersecting at 90 degrees resulting in a right-angled triangle.

FIG. 10A illustrates an isometric view 1000 of an eighth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theisometric view 1000 includes the first source assembly 1010A, the secondsource assembly 1010B and the output waveguide 1020.

Each of the first source assembly 1010A and the second source assembly010B is a set of optical components that perform a generation andconditioning of an image light. The first source assembly 1010A outputsan image light (not shown) to the output waveguide 1020. The secondsource assembly 1010B outputs an image light (not shown) to the outputwaveguide 1020.

The output waveguide 1020 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 1020 receives animage light (not shown) at the coupling element 1050A and the couplingelement 1050B, and guides the received input image light to thedecoupling element 1060A. In some embodiments, the coupling element1050A and the coupling element 1050B couple the image light from thefirst source assembly 1010A and the second source assembly 1010B intothe output waveguide 1020. The coupling element 1050A may be, e.g., adiffraction grating, a holographic grating, or some combination thereof.The coupling element 1050A has a first grating vector. The pitch of thecoupling element 950A may be 300-600 nm.

In one configuration, the eighth design of the waveguide displayprovides a horizontal field of view of 54.0 degrees, a vertical field ofview of 27.0 degrees, and a diagonal field of view of 60.4 degrees. Inanother configuration, the coupling element 1050A and the couplingelement 1050B include a pitch in the range of 300 nm to 600 nm, and thedecoupling elements 1060A and 1060B include a pitch in the range of 300nm to 600 nm. In yet another configuration, the first source assembly1010A and the second source assembly 1010B include a distance ofseparation of 20 mm.

FIG. 10B illustrates a top view 1005 of the eighth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Thetop view 1005 includes the coupling element 1050A, the coupling element1050B, the decoupling element 1060A, and the decoupling element 1060B ofthe output waveguide 1020.

FIG. 10C illustrates an example path 1015 of grating vectors associatedwith a plurality of diffraction gratings of the eighth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theexample path 1015 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 1050A, thecoupling element 1050B, the first decoupling element 1060A, and thesecond decoupling element 1060B that the image light meets. The gratingvectors are just added to change the path of the wave vector. In theexample path 1015, image light from each of the source assemblies (notshown here) is associated with a respective projected radial wave vector(not shown). The image light is coupled into the output waveguide 1020via the coupling element 1050A and the coupling element 1050B associatedwith a respective input grating vector (not shown). The in-coupled lightis then diffracted by the first decoupling element 1060A associated witha first grating vector (not shown). The light is then diffracted (andout coupled from the output waveguide 1020) by the second decouplingelement 1060B associated with a second grating vector (not shown). Inone embodiment, the example path 1015 includes a summation point 1065A.The summation of the input grating vector, the first grating vector, andthe second grating vector at the summation point 1065A is zero. In asecond embodiment, the example path 1015 includes a summation point1065B. The summation of the input grating vector, the first gratingvector, and the second grating vector at the summation point 1065B iszero. In some configurations, the example path 1015 is an equilateraltriangle with the same magnitude for the input wave vector, the firstgrating vector, and the second grating vector.

FIG. 11A illustrates an isometric view 1100 of a ninth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theisometric view 1100 includes the first source assembly 1110A, the secondsource assembly 1110B, and an output waveguide 1120.

Each of the first source assembly 1110A and the second source assembly1110B is a set of optical components that perform a generation andconditioning of an image light. The first source assembly 1110A outputsan image light (not shown) to the output waveguide 1120. The secondsource assembly 1110B outputs an image light (not shown) to the outputwaveguide 1120. The first source assembly 1110A and the second sourceassembly 1110B are located with a threshold value of distance ofseparation along the X-dimension, and at a central position along theY-dimension (e.g. mid-point of a side of the output waveguide 1120 alongthe Y-axis).

The output waveguide 1120 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 1120 receives animage light (not shown) at the coupling element 1150A and the couplingelement 1150B, and guides the received input image light to thedecoupling element 1160A. In some embodiments, the coupling element1150A and the coupling element 1150B couple the image light from thefirst source assembly 1110A and the second source assembly 1110B,respectively, into the output waveguide 1120. The coupling element 1150Amay be, e.g., a diffraction grating, a holographic grating, or somecombination thereof. The coupling element 1150A has a first gratingvector. The pitch of the coupling element 1150A may be 300-600 nm. Asshown in FIG. 11A, the first source assembly 1110A projects light intothe coupling element 1150A, and the second source assembly 1110Bprojects light into the coupling element 1150B, and the coupling element1150A and the coupling element 1150B are on the same surface along theX-Y plane, and the decoupling element 1160A is in between the couplingelement 1150A and the coupling element 1150B.

In one configuration, the ninth design of the waveguide display providesa horizontal field of view of 65.0 degrees, a vertical field of view of40.0 degrees, and a diagonal field of view of 76.3 degrees. In anotherconfiguration, the coupling element 1150A and the coupling element 1150Binclude a pitch in the range of 300 nm to 600 nm, and the decouplingelements 1160A and 1160B include a pitch in the range of 300 nm to 600nm.

FIG. 11B illustrates a top view 1105 of the ninth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Thetop view 1105 includes the coupling element 1150A, the coupling element1150B, the decoupling element 1160A, and the decoupling element 1160B ofthe output waveguide 1120.

FIG. 11C illustrates an example path 1115 of grating vectors associatedwith a plurality of diffraction gratings of the ninth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theexample path 1115 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 1150A, thecoupling element 1150B, the first decoupling element 1160A, and thesecond decoupling element 1160B that the image light meets. The gratingvectors are just added to change the path of the wave vector. In theexample path 1115, image light from each of the source assemblies (notshown here) is associated with a respective projected radial wave vector(not shown). The image light is coupled into the output waveguide 1120via the coupling element 1150A and the coupling element 1150B associatedwith a respective input grating vector (not shown). The in-coupled lightis then diffracted by the first decoupling element 1160A associated witha first grating vector (not shown). The light is then diffracted (andout coupled from the output waveguide 1120) by the second decouplingelement 1160B associated with a second grating vector (not shown). Inone embodiment, the example path 1115 includes a summation point 1165Aand a summation point 1165B. The summation of the input grating vector,the first grating vector, and the second grating vector at each of thesummation point 1165A and the summation point 1160B is zero. In a secondembodiment, the example path 1115 includes a summation point 1165C and asummation point 1165D. The summation of the input grating vector, thefirst grating vector, and the second grating vector at each of thesummation point 1165C and the summation point 1165D is zero. In someconfigurations, the example path 1115 is a pair of equilateral triangleswith the same magnitude for the input wave vector, the first gratingvector, and the second grating vector.

FIG. 12A illustrates an isometric view 1200 of the tenth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theisometric view 1200 includes a source assembly 1210, a source waveguide1215, and an output waveguide 1220.

The source assembly 1210 is a set of optical components that perform ageneration and conditioning of an image light. In some configurations,the source assembly 1210 includes a light source and an optics system(not shown here). For example, the light source generates an image lightand the optics system conditions the generated image light. The sourceassembly 1210 is an embodiment of the source assembly 610. The sourceassembly 1210 outputs an image light (not shown) to a source waveguide1215.

The source waveguide 1215 is an optical waveguide. The source waveguide1215 receives the image light from the source assembly 1210 and outputsan image light (not shown) to an output waveguide 1220. The image lightfrom the source waveguide 1215 propagates along a dimension with aninput wave vector as described below with reference to FIG. 12C.

The output waveguide 1220 is an optical waveguide that outputs imagelight to an eye 220 of a user. The output waveguide 1220 receives theimage light from the source waveguide 1215 at a coupling element 1250A,and guides the received input image light to a decoupling element 1260Aor a decoupling element 1260B.

The coupling element 1250A includes a width in the range of 10 mm to 20mm, a height in the range of 2 mm to 5 mm and a pitch in the range of0.3 to 0.6 micron. The decoupling element 1260A includes a width in therange of 10 mm to 20 mm, a height in the range of 2 mm to 5 mm and apitch in the range of 0.3 to 0.6 micron. The decoupling element 1260Bincludes a width in the range of 10 mm to 20 mm, a height in the rangeof 2 mm to 5 mm and a pitch in the range of 0.3 to 0.6 micron. In oneconfiguration, the tenth design of the waveguide display of FIG. 7provides a horizontal field of view of 51.0 degrees, a vertical field ofview of 31.9 degrees, and a diagonal field of view of 60.1°. In someconfigurations, the waveguide display of FIG. 7 includes the couplingelement 1250A with a pitch in the range of 300 nm to 600 nm, and thedecoupling elements 1260A and 1260B with a pitch in the range of 300 nmto 600 nm.

FIG. 12B illustrates a top view 1225 of the tenth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Thetop view 1225 includes the source assembly 1210, the source waveguide1215, and the output waveguide 1220.

FIG. 12C illustrates an example path 1230 of grating vectors associatedwith a plurality of diffraction gratings of the tenth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theexample path 1230 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element and thedecoupling elements that the image light meets. The grating vectors arejust added to change the path of the wave vector. In the example path1230, image light from the source assembly 1210 is associated with aprojected radial wave vector (not shown). The image light is coupledinto the output waveguide 1220 via the coupling element 1250A associatedwith an input grating vector (not shown). The in-coupled light is thendiffracted by the first decoupling element 1260A associated with a firstgrating vector (not shown). The light is then diffracted (and outcoupled from the output waveguide) by the second decoupling element1260B associated with a second grating vector (not shown). Note that thesummation of the projected radial wave vector at the summation point1255A is zero. Similarly, the summation of the input grating vector, thefirst grating vector, and the second grating vector at the summationpoint 1265A is zero. The summation point 1255B is an embodiment of thesummation point 1255A. The summation point 1265B is an embodiment of thesummation point 1265A.

The coupling element 1250A, the first decoupling element 1260A, and thesecond decoupling element 1260B, are diffraction gratings whose gratingvectors sum to a value that is less than a threshold value, and thethreshold value is close to or equal to zero. In this example, a zerosummation occurs, as the vector path returns to its origination point.With the occurrence of the zero summation, the image light exits theoutput waveguide 1220 with the same angle as the incident angle from thesource assembly 1210 since the remaining radial wave vector isassociated with the FOV of the waveguide display.

Note this is a very simple example, and there are many alternativeembodiments, as described below in conjunction with FIG. 12D to FIG.12I, including various diffraction gratings whose summation of gratingvectors returns to the origination point. For example, the path 1230 isshaped like an equilateral triangle with an equal magnitude of thegrating vectors, and other paths may be a hexagon, a pentagon, aparallelogram, a rectangle, or any other shape whose sum of gradientvectors is less than the threshold value.

FIG. 12D illustrates an isometric view of an eleventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theisometric view 1240 includes the source assembly 1210, a sourcewaveguide 1215D, and an output waveguide 1222.

The source waveguide 1215D is an optical waveguide. The source waveguide1215D receives the image light from the source assembly 1210 and outputsan image light (not shown) to an output waveguide 1222. The image lightfrom the source waveguide 1215D propagates along a dimension with aninput wave vector as described below with reference to FIG. 12F.

The output waveguide 1222 is an optical waveguide. The output waveguide1222 includes a coupling element 1250D, a decoupling element 1260D and adecoupling element 1260E. The coupling element 1250D is an embodiment ofthe coupling element 350. The decoupling element 1260D is an embodimentof the decoupling element 360A. The decoupling element 1260E is anembodiment of the decoupling element 360B. In one configuration, theeleventh design of the waveguide display of FIG. 12D provides ahorizontal field of view of 53.0 degrees, a vertical field of view of28.2 degrees, and a diagonal field of view of 60.0°. In anotherconfiguration, the coupling element 1250D includes a pitch in the rangeof 300 nm to 600 nm, and the decoupling element 1260D and the decouplingelement 1260E include a pitch in the range of 300 nm to 600 nm.

FIG. 12E illustrates a top view 1250 of the eleventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Thetop view 1250 includes the source assembly 1210, the source waveguide1215E, and the output waveguide 1222.

FIG. 12F illustrates an example path 1270 of grating vectors associatedwith a plurality of diffraction gratings of the eleventh design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theexample path 1270 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 1250D, thedecoupling element 1260D, and the decoupling element 1260E that theimage light meets. The grating vectors are just added to change the pathof the wave vector. The example path 1270 is an embodiment of theexample path 430.

FIG. 12G illustrates an isometric view 1205 of a twelfth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theisometric view 1205 includes the source assembly 1210, a sourcewaveguide 1215D, and an output waveguide 1222.

The source waveguide 1215D is an optical waveguide. The source waveguide1215D receives the image light from the source assembly 1210 and outputsan image light (not shown) to an output waveguide 1222. The image lightfrom the source waveguide 1215D propagates along a dimension with aninput wave vector as described below with reference to FIG. 12I.

The output waveguide 1222 is an optical waveguide. The output waveguide1222 includes a coupling element 1250D, a decoupling element 1260D and adecoupling element 1260E. The coupling element 1250D includes a width inthe range of 10 mm to 20 mm, a height in the range of 2 mm to 5 mm and apitch in the range of 0.3 to 0.6 micron. The decoupling element 1260Dincludes a width in the range of 10 mm to 20 mm, a height in the rangeof 2 mm to 5 mm and a pitch in the range of 0.3 to 0.6 micron. Thedecoupling element 1260E includes a width in the range of 10 mm to 20mm, a height in the range of 2 mm to 5 mm and a pitch in the range of0.3 to 0.6 micron.

FIG. 12H illustrates a top view 1275 of the twelfth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Thetop view 1275 includes the source assembly 1210, the source waveguide1215D, and the output waveguide 1222

FIG. 12I illustrates an example path of grating vectors associated witha plurality of diffraction gratings of the twelfth design of thewaveguide display shown in FIG. 7, in accordance with an embodiment. Theexample path 1285 is a path of a wave vector of the image light that isaffected by the grating vectors of the coupling element 1250D, the firstdecoupling element 1260D, and the second decoupling element 1260E thatthe image light meets. The grating vectors are just added to change thepath of the wave vector. In the example path 1285, image light from thesource assembly 1210 is associated with a projected radial wave vector(not shown). The image light is coupled into the output waveguide 1222via the coupling element 1250D associated with an input grating vector(not shown). The in-coupled light is then diffracted by the firstdecoupling element 1260D associated with a first grating vector (notshown). The light is then diffracted (and out coupled from the outputwaveguide) by the second decoupling element 1260E associated with asecond grating vector (not shown). In one embodiment, the example path1285 includes a first summation point 1255C, and a second summationpoint 1265C. Note that the summation of the projected radial wave vectorat the first summation point 1255C is zero. The summation of the inputgrating vector, the first grating vector, and the second grating vectorat the second summation point 1265C is zero. In a second embodiment, theexample path 1285 includes the first summation point 12555C, a thirdsummation point 1265D, and a fourth summation point 1265E. The summationof the input grating vector, the first grating vector, and the secondgrating vector at the third summation point 1265D is zero. Similarly,the summation of the input grating vector, the first grating vector, andthe second grating vector at the fourth summation point 1265E is alsozero.

In an alternate configuration, the example path 1285 includes a fifthsummation point 1255D, and the first summation point 1265C. The fifthsummation point 1255D is an embodiment of the first summation point1255C. In yet another configuration, the example path 1285 includes thefifth summation point 1255D, the third summation point 1265D, and thefourth summation point 1265E.

FIG. 13 is a block diagram of a system 1300 including the NED 100 ofFIG. 1, according to an embodiment. The system 1300 shown by FIG. 13comprises the NED 100, an imaging device 1335, and an input/outputinterface 1340 that are each coupled to the console 1310. While FIG. 13shows an example system 1300 including one NED 100, one imaging device1335, and one input/output interface 1340, in other embodiments, anynumber of these components may be included in the system 1300. Forexample, there may be multiple NEDs 100 each having an associatedinput/output interface 1340 and being monitored by one or more imagingdevices 1335, with each NED 100, input/output interface 1340, andimaging devices 1335 communicating with the console 1310. In alternativeconfigurations, different and/or additional components may be includedin the system 1300. Similarly, functionality of one or more of thecomponents can be distributed among the components in a different mannerthan is described here. For example, some or all of the functionality ofthe console 1310 may be contained within the NED 100. Additionally, insome embodiments the system 1300 may be modified to include other systemenvironments, such as an AR system environment and/or a mixed reality(MR) environment.

The NED 100 is a near-eye display that presents media to a user.Examples of media presented by the NED 100 include one or more images,video, audio, or some combination thereof. In some embodiments, audio ispresented via an external device (e.g., speakers and/or headphones) thatreceives audio information from the NED 100, the console 1310, or both,and presents audio data based on the audio information. In someembodiments, the NED 100 may also act as an AR eye-wear glass. In theseembodiments, the NED 100 augments views of a physical, real-worldenvironment with computer-generated elements (e.g., images, video,sound, etc.).

The NED 100 includes a waveguide display assembly 1315, one or moreposition sensors 1325, and the inertial measurement unit (IMU) 1330. Thewaveguide display assembly 1315 includes the source assembly 310, theoutput waveguide 320, and the controller 330 of FIG. 3 The outputwaveguide 320 includes multiple diffraction gratings such that lightentering the output waveguide 320 exits the waveguide display assembly1315 at the same angle. Details for various embodiments of the waveguidedisplay element are discussed in detail with reference to FIGS. 3 and 4.In another embodiment, the waveguide display assembly 1315 includes thesource assembly 610, the output waveguide 620, and the controller 330,as described above with reference to FIGS. 6 and 7. In an alternateembodiment, the waveguide display assembly 1315 includes the firstsource assembly 1110A, the second source assembly 910B, the outputwaveguide 920, and the controller 330, as described above with referenceto FIGS. 9 and 10. The waveguide display assembly includes, e.g., awaveguide display, a stacked waveguide display, a varifocal waveguidedisplay, or some combination thereof.

The IMU 1330 is an electronic device that generates fast calibrationdata indicating an estimated position of the NED 100 relative to aninitial position of the NED 100 based on measurement signals receivedfrom one or more of the position sensors 1325. A position sensor 1325generates one or more measurement signals in response to motion of theNED 100. Examples of position sensors 1325 include: one or moreaccelerometers, one or more gyroscopes, one or more magnetometers, asuitable type of sensor that detects motion, a type of sensor used forerror correction of the IMU 1330, or some combination thereof. Theposition sensors 1325 may be located external to the IMU 1330, internalto the IMU 1330, or some combination thereof. In the embodiment shown byFIG. 13, the position sensors 1325 are located within the IMU 1330, andneither the IMU 1330 nor the position sensors 1325 are visible to theuser (e.g., located beneath an outer surface of the NED 100).

Based on the one or more measurement signals generated by the one ormore position sensors 1325, the IMU 1330 generates fast calibration dataindicating an estimated position of the NED 100 relative to an initialposition of the NED 100. For example, the position sensors 1325 includemultiple accelerometers to measure translational motion (forward/back,up/down, left/right) and multiple gyroscopes to measure rotationalmotion (e.g., pitch, yaw, roll). In some embodiments, the IMU 1325rapidly samples the measurement signals from various position sensors1325 and calculates the estimated position of the NED 100 from thesampled data. For example, the IMU 1330 integrates the measurementsignals received from one or more accelerometers over time to estimate avelocity vector and integrates the velocity vector over time todetermine an estimated position of a reference point on the NED 100. Thereference point is a point that may be used to describe the position ofthe NED 100. While the reference point may generally be defined as apoint in space; however, in practice, the reference point is defined asa point within the NED 100.

The imaging device 1335 generates slow calibration data in accordancewith calibration parameters received from the console 1310. The imagingdevice 1335 may include one or more cameras, one or more video cameras,any other device capable of capturing images, or some combinationthereof. Additionally, the imaging device 1335 may include one or morefilters (e.g., used to increase signal to noise ratio). Slow calibrationdata is communicated from the imaging device 1335 to the console 1310,and the imaging device 1335 receives one or more calibration parametersfrom the console 1310 to adjust one or more imaging parameters (e.g.,focal length, focus, frame rate, ISO, sensor temperature, shutter speed,aperture, etc.).

The input/output interface 1340 is a device that allows a user to sendaction requests to the console 1310. An action request is a request toperform a particular action. For example, an action request may be tostart or end an application or to perform a particular action within theapplication. The input/output interface 1340 may include one or moreinput devices. Example input devices include: a keyboard, a mouse, agame controller, or any other suitable device for receiving actionrequests and communicating the received action requests to the console1310. An action request received by the input/output interface 1340 iscommunicated to the console 1310, which performs an action correspondingto the action request. In some embodiments, the input/output interface1340 may provide haptic feedback to the user in accordance withinstructions received from the console 1310. For example, hapticfeedback is provided when an action request is received, or the console1310 communicates instructions to the input/output interface 1340causing the input/output interface 1340 to generate haptic feedback whenthe console 1310 performs an action.

The console 1310 provides media to the NED 100 for presentation to theuser in accordance with information received from one or more of: theimaging device 1335, the NED 100, and the input/output interface 1340.In the example shown in FIG. 13, the console 1310 includes anapplication store 1345, a tracking module 1350, and an engine 1355. Someembodiments of the console 1310 have different modules than thosedescribed in conjunction with FIG. 13. Similarly, the functions furtherdescribed below may be distributed among components of the console 1310in a different manner than is described here.

The application store 1345 stores one or more applications for executionby the console 1310. An application is a group of instructions, thatwhen executed by a processor, generates content for presentation to theuser. Content generated by an application may be in response to inputsreceived from the user via movement of the NED 100 or the input/outputinterface device 1340. Examples of applications include: gamingapplications, conferencing applications, video playback application, orother suitable applications.

The tracking module 1350 calibrates the system 1300 using one or morecalibration parameters and may adjust one or more calibration parametersto reduce error in determination of the position of the NED 100. Forexample, the tracking module 1350 adjusts the focus of the imagingdevice 1335 to obtain a more accurate position for observed locators onthe system 1300. Moreover, calibration performed by the tracking module1350 also accounts for information received from the IMU 1330.

The tracking module 1350 tracks movements of the NED 100 using slowcalibration information from the imaging device 1335. The trackingmodule 1350 also determines positions of a reference point of the NED100 using position information from the fast calibration information.Additionally, in some embodiments, the tracking module 1350 may useportions of the fast calibration information, the slow calibrationinformation, or some combination thereof, to predict a future locationof the NED 100. The tracking module 1350 provides the estimated orpredicted future position of the NED 100 to the VR engine 1355.

The engine 1355 executes applications within the system 1300 andreceives position information, acceleration information, velocityinformation, predicted future positions, or some combination thereof ofthe NED 100 from the tracking module 1350. In some embodiments, theinformation received by the engine 1355 may be used for producing asignal (e.g., display instructions) to the waveguide display assembly1315 that determines the type of content presented to the user. Forexample, if the received information indicates that the user has lookedto the left, the engine 1355 generates content for the NED 100 thatmirrors the user's movement in a virtual environment by determining thetype of source and the waveguide that must operate in the waveguidedisplay assembly 1315. For example, the engine 1355 may produce adisplay instruction that would cause the waveguide display assembly 1315to generate content with red, green, and blue color. Additionally, theengine 1355 performs an action within an application executing on theconsole 1310 in response to an action request received from theinput/output interface 1340 and provides feedback to the user that theaction was performed. The provided feedback may be visual or audiblefeedback via the NED 100 or haptic feedback via the input/outputinterface 1340.

Additional Configuration Information

The foregoing description of the embodiments of the disclosure has beenpresented for the purpose of illustration; it is not intended to beexhaustive or to limit the disclosure to the precise forms disclosed.Persons skilled in the relevant art can appreciate that manymodifications and variations are possible in light of the abovedisclosure.

Some portions of this description describe the embodiments of thedisclosure in terms of algorithms and symbolic representations ofoperations on information. These algorithmic descriptions andrepresentations are commonly used by those skilled in the dataprocessing arts to convey the substance of their work effectively toothers skilled in the art. These operations, while describedfunctionally, computationally, or logically, are understood to beimplemented by computer programs or equivalent electrical circuits,microcode, or the like. Furthermore, it has also proven convenient attimes, to refer to these arrangements of operations as modules, withoutloss of generality. The described operations and their associatedmodules may be embodied in software, firmware, hardware, or anycombinations thereof.

Any of the steps, operations, or processes described herein may beperformed or implemented with one or more hardware or software modules,alone or in combination with other devices. In one embodiment, asoftware module is implemented with a computer program productcomprising a computer-readable medium containing computer program code,which can be executed by a computer processor for performing any or allof the steps, operations, or processes described.

Embodiments of the disclosure may also relate to an apparatus forperforming the operations herein. This apparatus may be speciallyconstructed for the required purposes, and/or it may comprise ageneral-purpose computing device selectively activated or reconfiguredby a computer program stored in the computer. Such a computer programmay be stored in a non-transitory, tangible computer readable storagemedium, or any type of media suitable for storing electronicinstructions, which may be coupled to a computer system bus.Furthermore, any computing systems referred to in the specification mayinclude a single processor or may be architectures employing multipleprocessor designs for increased computing capability.

Embodiments of the disclosure may also relate to a product that isproduced by a computing process described herein. Such a product maycomprise information resulting from a computing process, where theinformation is stored on a non-transitory, tangible computer readablestorage medium and may include any embodiment of a computer programproduct or other data combination described herein.

Finally, the language used in the specification has been principallyselected for readability and instructional purposes, and it may not havebeen selected to delineate or circumscribe the inventive subject matter.It is therefore intended that the scope of the disclosure be limited notby this detailed description, but rather by any claims that issue on anapplication based hereon. Accordingly, the disclosure of the embodimentsis intended to be illustrative, but not limiting, of the scope of thedisclosure, which is set forth in the following claims.

What is claimed is:
 1. A waveguide system comprising: a coupling elementfor in-coupling light into a waveguide, the coupling element changingthe direction of the wavevector by a first amount; a firstone-dimensional decoupling grating configured to receive light from thewaveguide and to change the direction of the wavevector by a secondamount by diffracting at least a first portion of the in-coupled light;a second one-dimensional decoupling grating configured to change thedirection of the wavevector by a third amount by diffracting at least asecond portion of the in-coupled light and to output the redirectedlight to an eyebox, the second one-dimensional decoupling grating facingopposite the first one-dimensional decoupling grating, a total amount ofthe first amount, second amount, and third amount being predeterminedbased on a location of the eyebox, wherein the first one-dimensionaldecoupling grating and the second one-dimensional decoupling gratingsubstantially overlaps along a direction parallel to a surface of thewaveguide.
 2. The waveguide system of claim 1, wherein the total amountis substantially zero.
 3. The waveguide system of claim 1, wherein thefirst one-dimensional decoupling grating is a diffraction grating andwherein the first portion of the in-coupled light is based on anincident location of the in-coupled light.
 4. The waveguide system ofclaim 3, wherein the first one-dimensional decoupling grating isconfigured to adjust the first portion of the in-coupled light based onan output angle of inclination of the diffracted first portion of thein-coupled light.
 5. The waveguide system of claim 1, wherein the secondone-dimensional decoupling grating is a diffraction grating and whereinthe second portion of the in-coupled light is based on a location of anincident location of the in-coupled light.
 6. The waveguide system ofclaim 5, wherein the second one-dimensional decoupling grating isconfigured to adjust the second portion of the in-coupled light based onan output angle of inclination of the diffracted second portion of thein-coupled light.
 7. The waveguide system of claim 1, wherein a pitch ofat least one of the coupling element, the first one-dimensionaldecoupling grating, and the second one-dimensional decoupling grating isin a range of 300-600 nm.
 8. The waveguide system of claim 1, whereinthe waveguide is configured to expand the in-coupled light in at leastone dimension.
 9. The waveguide system of claim 8, wherein each of thesecond one-dimensional decoupling grating and the third one-dimensionaldecoupling grating is configured to expand the in-coupled image lightalong a different dimension and to out-couple the redirected light alonga third dimension.
 10. The waveguide system of claim 1, wherein thewaveguide is configured to expand the in-coupled light in at least onedimension parallel to the surface of the waveguide.
 11. The waveguidesystem of claim 1, wherein the coupling element and the firstone-dimensional decoupling grating are separated by a distance at leastalong a first dimension and a second dimension orthogonal to the firstdimension along the surface of the waveguide, and the first couplingelement and the second one-dimensional decoupling grating located at acentral position along the second dimension.
 12. The waveguide system ofclaim 1, wherein the coupling element is a diffraction grating on atleast a first surface and a second surface of the waveguide, thecoupling element configured to couple a first angular range and a secondangular range of the light, and the second surface is opposite to thefirst surface.
 13. The waveguide system of claim 12, wherein the firstportion of light and the second portion of light are in the firstangular range, the first one-dimensional decoupling grating expands thefirst portion of light to the second dimension, and the secondone-dimensional decoupling grating expands the second portion of lightto the second dimension.
 14. The waveguide system of claim 1, whereinthe first one-dimensional decoupling grating and the secondone-dimensional decoupling grating are located on the surface of thewaveguide with an interfacial layer between the first one-dimensionaldecoupling grating and the second one-dimensional decoupling grating.15. The waveguide system of claim 1, wherein the first one-dimensionaldecoupling grating and the second one-dimensional decoupling grating areembedded into the waveguide and separated by an interfacial layer. 16.The waveguide system of claim 1, wherein the coupling element includes afirst grating element and a second grating element separated along afirst dimension parallel to the surface of the waveguide.
 17. Thewaveguide system of claim 16, wherein the second one-dimensionaldecoupling grating is located between the first grating element and thesecond grating element, and the second one-dimensional decouplinggrating is located at a central location on a second dimension betweenthe first grating element and the second grating element, the seconddimension orthogonal to the first dimension.
 18. The waveguide system ofclaim 1, wherein the coupling element is a refractive surface.
 19. Thewaveguide system of claim 1, wherein the first one-dimensionaldecoupling grating includes one or more cascaded reflectors configuredto deflect the in-coupled light over an angular range, and the secondone-dimensional decoupling grating includes one or more cascadedreflectors configured to output the deflected light to the eyebox. 20.The waveguide system of claim 1, wherein the waveguide system provides adiagonal FOV of at least 60 degrees.